Jets and metering rods question...

[ChadW]

I posted this in the engine and drivetrain forum but got no hits...thought id stick it here and see as well..
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I have a Holley Street Demon 625 and this carb uses metering rods...I have never dealt with them..here is my question...

so say i have a .080 primary jet in it with a 6052 rod (.060 and.052 step)

would that be the exact same as having a .076 jet with a 5648 rod? I came up with this by deducting the step sizes from the jet sizes...

Both come out .020 and .028...

Trying to find out where to start when you run our of metering rod adjustments and need to do a jet change...

[geezer#99]

With other carbs like the quadrajet or Carter afb I’ve always changed rods first.

Maybe some info in this link.


https://www.chevyhardcore.com/tech-s...on-carburetor/

[Grounded63]

No, it's not the same. Because the .080 jet flows more than the .076 jet. And adding a equally proportional restriction doesn't change that. The .076 jet with a .056 metering rod will be slightly leaner. At .055 very,very slightly leaner. At .054 very slightly richer. Now that's all based on area calculations. And not actual fluid dynamics, fyi.